environmentaltools.spatiotemporal.indicators.multivariate_threshold_exceedance

environmentaltools.spatiotemporal.indicators.multivariate_threshold_exceedance(cube_list, thresholds)[source]

Calculate frequency of simultaneous threshold exceedance for multiple variables.

Computes how often all variables simultaneously exceed their respective thresholds. This is useful for identifying areas prone to compound environmental extremes.

Parameters:

  • cube_list (list of np.ndarray) – List of 3D arrays (time, lat, lon), one per variable.

  • thresholds (list of float) – List of threshold values, one per variable.

Returns:

exceedance_map – 2D map of simultaneous exceedance frequency (0-1 scale).

Return type:

np.ndarray

Notes

The function identifies time steps when ALL variables exceed their respective thresholds simultaneously. This is more restrictive than individual threshold exceedances and identifies true compound events.

Examples

>>> import numpy as np
>>> cube1 = np.random.exponential(2, (50, 15, 15))
>>> cube2 = np.random.gamma(2, 1, (50, 15, 15))
>>> freq_map = multivariate_threshold_exceedance([cube1, cube2], [3.0, 2.5])